Airfoil construction

ABSTRACT

An aircraft having an airfoil provided with a plurality of openings on the upper lift surface thereof for directing an airflow over substantially the entire area of that surface. This flow decreases the pressure over the upper lift surface for creating lift forces sufficient to lift the aircraft. The size of the opening is varied by means of a selectively positionable, pivotal flap. A wall portion cooperating with the flap to form the opening may have one of several configurations including planar, a wedge, and an isosceles triangle with its apex adjacent the outer end of the flap. Further, an upper airfoil shaped member may be arranged at the lift surface of the airfoil adjacent the opening. Openings in various portions of the wings may be inversely positionable from symmetrically arranged openings for controlling the attitude of the aircraft. A propeller is arranged for ducting air to the openings. This propeller, which may be supplemented by at least one compressor stage, has variable and reversible pitch tips for selectively and variably providing thrust bidirectionally along the trust line of the aircraft. When positioned for reversed thrust, these tips will provide a thrust which counters any thrust created by air escaping from the openings and permit the aircraft to hover. The airfoil is also provided with passages therethrough arranged in symmetrically spaced portions thereof in parallel to the aircraft thrust line. These passages have valves associated therewith and arranged for selectively and inversely directing airflow from the passages for imparting a moment to the airfoil which permits turning of the aircraft.

ited States Patent 1191 Tibbs Oct. 28, 1975 54] AIRFOIL CONSTRUCTION[76] Inventor: Robert C. Tibbs, Hospital Drive,

Cleveland, Miss. 38732 [22] Filed: July 12, 1974 [21] Appl. No.: 488,241

Related U.S. Application Data [62] Division of Ser. No. 251,686, May 9,1972, Pat. No.

Primary ExaminerDuane A. Reger Attorney, Agent, or FirmClarence A.OBrien & Harvey B. Jacobson [57] ABSTRACT An aircraft having an airfoilprovided with a plurality of openings on the upper lift surface thereoffor directing an airflow over substantially the entire area of thatsurface. This flow decreases the pressure over the upper lift surfacefor creating lift forces sufficient to lift the aircraft. The size ofthe opening is varied by means of a selectively positionable, pivotalflap. A wall portion cooperating with the flap to form the opening mayhave one of several configurations including planar, a wedge, and anisosceles triangle with its apex adjacent the outer end of the flap.Further, an upper airfoil shaped member may be arranged at the liftsurface of the airfoil adjacent the opening. Openings in variousportions of the wings may be inversely positionable from symmetricallyarranged openings for controlling the attitude of the aircraft. Apropeller is arranged for ducting air to the openings. This propeller,which may be supplemented by at least one compressor stage, has variableand reversible pitch tips for selectively and variably providing thrustbidirectionally along the trust line of the aircraft. When positionedfor reversed thrust, these tips will provide a thrust which counters anythrust created by air escaping from the openings and permit the aircraftto hover. The airfoil is also provided with passages therethrougharranged in symmetrically spaced portions thereof in parallel to theaircraft thrust line. These passages have valves associated therewithand arranged for selectively and inversely directing airflow from thepassages for imparting a moment to the airfoil which permits turning ofthe aircraft.

4 Claims, 15 Drawing Figures US. Patent Oct. 28, 1975 Sheet20f53,915,412

NM U

US. Patent Oct.28, 1975 Sheet 3 of5 3,915,412

Sheet 4 of5 3,915,412

US. Patent Oct. 28, 1975 AIRFOIL CONSTRUCTION This is a division ofapplication Ser. No. 251,686, filed May 9, 1972, now US. Pat. No.3,840,199.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to an aircraft, and particularly to an airplane capable ofhorizontal attitude, vertical takeoff and landing by means lift forcescreated by the movement of air over the upper lift surface of ahorizontal airfoil. The movement of air is provided other than by themovement of the airfoil relative to ambient air.

2. Description of the Prior Art As has long been known, lift forces arecreated on a horizontal airfoil by so configuring the airfoil that airpasses over the upper surface thereof in such a manner as to decreasethe pressure over the upper surface to a value lower than the pressureadjacent the lower surface of the airfoil. It has also been longrecognized that the flow of air over the upper surface of the airfoilmay be originated in a manner other than by relative movement of theairfoil with respect to ambient air. Known airfoils attempting toprovide a flow of air over the upper surface of an airfoil by meansother than such relative movement have invariably resorted to the use ofsymmetrical, generally cupshaped airfoils. An example of such an airfoilmay be found in US. Pat. No. 3,463,4l7. The reason for the symmetricalairfoils is that only in this manner could hovering capabilities beachieved for the aircraft. If the flow of air over the upper surface ofthe airfoil is not symmetrical, a thrust will be created in apredetermined direction.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a vertical takeoff and landing aircraft which has unsymmetricalairflow over the upper surface of a horizontal airfoil, but is stillcapable of hovering.

It is another object of the present invention to provide a verticaltakeoff and landing aircraft which may take off and land while inhorizontal or flying attitude.

It is yet another object of the present invention to provide such anaircraft which may be in the general configuration of a conventionalairplane, and which has general aerodynamic capabilities of conventionalairplanes and particularly gliding capabilities.

These and other objects are achieved according to the present inventionby providing an aircraft including an airfoil having a surface withmeans provided thereon for directing a fluid flow over substantially theentire area thereof and decreasing the pressure thereover for creatinglift forces sufficient to lift the aircraft. Means are provided on theaircraft for supplying fluid to the directing means.

According to a preferred embodiment of an airfoil according to thepresent invention, the directing means has at least one opening providedon the upper airfoil surface, and means for varying thesize of theopening. Advantageously, there are a plurality of openings arrangedabout the area of the airfoil surface, and the varying means is aselectively positionable, pivotal flap for each opening. At least oneopening in one portion To permit the aircraft to hover, means areprovided for selectively and variably providing thrust bidirectionallyalong the thrust line of the aircraft. This thrust providing means maybe at least one variable and reversible pitch tip on a propeller whichforms at least a portion of the supplying means. The propellercooperates with means for ducting fluid therefrom to the directingmeans. Alternatively, the supplying means may further have at least onecompressor stage arranged in the ducting means.

The airfoil is advantageously provided with passages therethrougharranged in symmetrically spaced portions thereof and substantiallyparallel to the thrust line. Means are associated with these passagesfor selectively and inversely directing fluid flow from the passages forimparting a moment to the airfoil and, thus, the aircraft. This momentis utilized in turning the aircraft, particularly during hovering andlow speed flying.

In one preferred embodiment according to the present invention, thereare a pair of airfoils connected to a fuselage, and the ducting means isarranged partially in the fuselage and partially in the airfoils.Alternatively, other configurations may be employed that generallycorrespond to conventional configurations of airplanes.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view, partly cutaway, showing an aircraft according to the present invention.

FIG. 2 is a front elevational view showing the aircraft of FIG. 1.

FIG. 3 is a side elevational view showing the aircraft of FIGS. 1 and 2.

FIG. 4 is a transverse sectional view showing an airfoil of the aircraftof FIGS. 1 to 3.

FIG. 5 is a detail view showing a fluid supplying and thrust providingsystem for use with an aircraft according to FIGS. 1 to 3.

FIG. 6 is a fragmentary, top plan view showing a modified constructionof an aircraft according to the present invention.

FIGS. 7 and 8 are fragmentary, plan, sectional views showing a wing tipcontrol assembly according to the present invention.

FIGS. 9 and 10 are front elevational views showing modified embodimentsof aircraft according to the present invention.

FIGS. 1 1 to 15 are fragmentary, transverse sectional views showingseveral embodiments of airfoil exit openings according to the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 of the drawingsshow an aircraft 10 according to the present invention having a fuselage12 provided with a cockpit 14, a pair of Wings 16, 18, stabilizers 20,22, and a rudder 24. The general configuration of aircraft 10 may becomparable to conventional airplanes.

Referring now to FIG. 4 in addition to FIGS. 1 to 3, wings 16, 18, whichare preferably horizontal airfoils,

each has an upper surface 26 provided with a plurality of openings 28defining exit ports and arranged for directing a flow of a fluid such asair over substantially the entire area of surface 26. This airflow willdecrease the pressure over surface 26 and create lift forces on wings16, 18. By proper design, these lift forces may be sufficient to liftaircraft I0. Selectively positionable flaps 30 are pivotally mounted atopenings 28 for varying the size of the exit ports.

At least one opening 28, and preferably a plurality thereof, in oneportion of surface 26 is selectively positionable inversely to at leastone opening in a symmetrically spaced portion of surface 26 forcontrolling the attitude of aircraft l0. Flaps 30 may have amacrocontrol settable from cockpit 14. This control would have fixedsettings of, for example, one-half inch intervals. This control may beactuated from a wheel or stick (not shown) arranged in cockpit 14. Theconnections between such a wheel or stick and flaps 30 are not shown,but may be of any conventional, well-known construction. Flaps 30 mayalso have micro-control which may also be actuated by the wheel orstick. This control may increase or decrease the openings 28 by only,for example, l/l6 inch to A inch increments. The macro-control may beused primarily or exclusively to control the size of openings 28 as afunction of airflow volume desired, while the micro-control may beprimarily or exclusively the inversely positionable control to functionin the manner of ailerons and tabs on conventional airplanes.

Reducing the size of openings 28 will, other factors being constant,cause an increase in the velocity of air over surface 26 with aresulting increase in lift.

Aircraft is further provided with a propeller 32 for supplying fluid toopenings 28. The fluid, or air is ducted from propeller 32 to openings28 by means of a duct 34 in fuselage l2 and plenums 36 (FIG. 4) in Wings16, 18. Propeller 32 is provided with variable and reversible pitch tips38 for variably providing thrust bidirectionally along thrust line A-A(FIG. 3) of aircraft 10. This reversible thrust feature permits aircraft10 to hover. As is conventional with propellers having variable pitchtips, a mechanism employing, for example, a hydraulic piston (not shown)mounted on a hub 40 with feed through the propeller shaft and withrotation of tips 38 by means of gears or links may be used. The linksbetween tips 38 and hub 40 may pass through hollow blades of propeller32. Electric motors and direct mechanical drives may also be used inplace of the hydraulic piston. Further, it is to be understood that theblades of propeller 32 may also be adjustable if desired for permittingthe quantity of air directed into duct 34 to be varied. Lowandhigh-pitch stops may be provided with the pitch-change mechanism, as isconventional. The removal of the low-pitch stop will permit the tips 38to move into reverse pitch positions. The high-pitch stop could also beselectively removable if desired. Advantageously, the pitch stops couldbe eliminated altogether, with a continuous positioning of tips 38through both the reverse and positive pitch ranges being alwaysavailable. Since the construction of pitchchange mechanisms is wellknown, and conventional mechanisms may be used with an aircraft 10according to the present invention, the construction thereof has notbeen set out in detail herein. I

Referring now to FIG. 5 of the drawings, in addition to propeller 32,there may be provided one or more compressor stages 42 arranged on apropeller shaft 44 which is operably connected in a known manner to aconventional aircraft engine 46. Engine 46 may be of any suitable, knowntype, including internal combustion, gas turbine, and the like.Compressor stages 42 are advantageously arranged in duct 34 forsupplementing the airflow creating capabilities of propeller 32.

As an alternative to the arrangement for aircraft 10 shown in FIGS. 1 to3, an aircraft according to the present invention may have theconfiguration shown in FIG. 6 of the drawings. In this modification,airfoils 48, 50 extend to the tail portion of a fuselage 12 with theresulting elimination of stabilizers 20, 22.

FIGS. 7 and 8 of the drawings show an advantageous feature of thepresent invention wherein each airfoil, or wing l6, 18, is provided withat least one passage 52 therethrough, and arranged in symmetricallyspaced portions thereof and substantially parallel to thrust line AA.These passages 52 are preferably arranged in the tips of the airfoils,and may be formed by passage portions 54, 56. Valves 58 may be pivotallymounted between portions 54, 56 as by pins 60 for actuation by controllines 62 for selectively and inversely directing airflow from plenum 36and out passages 52 for imparting a moment to the airfoil. That is,valve 58 will be positioned in a known manner to direct airflow out ofportion 54in one tip of the airfoil and from passages 56 in the tip ofanother airfoil. The resulting moment will permit the aircraft 10 toturn about its yaw axis even while hovering. Lines 62 may be connectedin a conventional manner to rudder pedal (not shown). In addition, themicro-control referred to above may be employed to bank the aircraftsimultaneously with the moment applied by use of passages 52. It is alsoto be understood that conventional ailerons may be used on the airfoilsif so desired.

FIG. 9 of the drawings shows an aircraft 64 according to the presentinvention in the form of a single engine, high wing monoplane having asingle airfoil 66 and propeller 67 arranged above a fuselage 64. FIG. 10of the drawings shows a multiengine aircraft 70 according to the presentinvention having a pair of airfoils 72, 74 provided with engines drivingpropellers 76, 78, respectively. Airfoils 66, and 72, 74 of aircraft 64,70 have openings (not shown) in the upper surface of respective airfoils66 and 72, 74 which function in a like manner to openings 28, ofaircraft 10. Aircrafts 64, 70 operate in an identical manner to aircraft10, the only difference being changes in configuration.

In yet another alternative embodiment of the present invention (notshown) a cockpit may actually form part of the airfoil. The differentconfigurations realizable within the scope of the present invention arepractically limitless, with even, for example, saucer-shaped airfoilsbeing possible.

The exit ports defined by openings 28 may take on a variety ofconfigurations and arrangements. FIG. 11 shows in detail the arrangementillustrated in FIG. 4. In this embodiment, the wall portion arrangedopposite flap 30 for defining opening 28 is a wedge-shaped portion 29inclined away from surface 26 in the direction of fluid flow. In FIG.12, an opening 128 is shown defined by a planar wall portion 129, whilein FIG. 13 an opening 228 is defined by a substantially isoscelestriangle having its apex adjacent the outer end of flap 30. Finally,FIG. 14 shows another possible configuration for the exit ports whereinthe lift surface adjacent an opening 328 is defined by a wall portion329 in the form of an upper airfoil surface. Each of the configurationsshown in FIGS. 11 to 14 of the drawings will provide a different liftfor a given airflow out of the respective opening. Specifically, theconstruction of the embodiment of FIG. 11 will reduce the pressure overthe lift surfaces of an airfoil l6, 18 more than the construction ofFIG. 12 will reduce the pressure over the lift surfaces of an airfoil116, 118. The airfoil-like configurations of the embodiments illustratedin FIGS. 13 and 14 will in a like manner affect the airflow over thelift surfaces of airfoils 216, 218, and 316, 318, respectively. Inparticular, the configuration of the wall portions 229 and 329 willcause a flow on a reduced scale similar to that which results when aconventional airfoil moves relative to air.

FIG. 15 shows yet another embodiment of an airfoil according to thepresent. invention. Basically, the embodiment of FIG. 15 is like that ofFIG. 12, but with a member 80 arranged on wall portion 129 and spacedtherefrom as by struts 82. Member 80 is preferably formed in the shapeof a conventional airfoil. High velocity fluid (air) from exit port 128passes over both the upper and lower airfoil surfaces of member 80.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. An aircraft comprising, in combination:

a. an airfoil having a surface;

b. means provided on said surface for directing a fluid flow oversubstantially the entire area thereof and decreasing the pressurethereover for creating lift forces sufficient to lift the aircraft; and

0. means for supplying fluid to the directing means, the directing meansbeing partially formed by a wall portion having a cross section in theform of a wedge inclined away from said surface and the airfoil in thedirection of fluid flow.

2. An aircraft comprising, in combination:

a. an airfoil having a surface;

b. means provided on said surface for directing a fluid flow oversubstantially the entire area thereof and decreasing the pressurethereover for creating lift forces sufficient to lift the aircraft; and

c. means for supplying fluid to the directing means, the directing meansincluding an opening partially defined by a pair of spaced, parallel,planar wall portions, and flap means pivotally mounted on one of thewall portions for varying the size of the opening.

3. An aircraft comprising, in combination:

a. an airfoil having a surface;

b. means provided on said surface for directing a fluid flow oversubstantially the entire area thereof and decreasing the pressurethereover for creating lift forces sufficient to lift the aircraft; and

c. means for supplying fluid to the directing means, the directing meansincluding at least one opening provided on said surface, and means forvarying the size of said opening, the varying means being a selectivelypositionable, pivotally mounted flap, and the directing means includingan opening partially defined by a wall portion having a cross sectionsubstantially in the form of an isosceles triangle having its apexadjacent an outer end of said flap.

4. An aircraft comprising, in'combination:

a. an airfoil having a surface;

b. means provided on said surface for directing a fluid flow oversubstantially the entire area thereof and decreasing the pressurethereover for creating lift forces sufficient to lift the aircraft; and

0. means for supplying fluid to the directing means, the directing meansincluding an opening, and said surface having a member arranged thereonspaced from the opening and formed in the shape of an upper airfoilsurface for receiving fluid flow from said opening.

1. An aircraft comprising, in combination: a. an airfoil having asurface; b. means provided on said surface for directing a fluid flowover substantially the entire area thereof and decreasing the pressurethereover for creating lift forces sufficient to lift the aircraft; andc. means for supplying fluid to the directing means, the directing meansbeing partially formed by a wall portion having a cross section in theform of a wedge inclined away from said surface and the airfoil in thedirection of fluid flow.
 2. An aircraft comprising, in combination: a.an airfoil having a surface; b. means provided on said surface fordirecting a fluid flow over substantially the entire area thereof anddecreasing the pressure thereover for creating lift forces sufficient tolift the aircraft; and c. means for supplying fluid to the directingmeans, the directing means including an opening partially defined by apair of spaced, parallel, planar wall portions, and flap means pivotallymounted on one of the wall portions for varying the size of the opening.3. An aircraft comprising, in combination: a. an airfoil having asurface; b. means provided on said surface for directing a fluid flowover substantially the entire area thereof and decreasing the pressurethereover for creating lift forces sufficient to lift the aircraft; andc. means for supplying fluid to the directing means, the directing meansincluding at least one opening provided on said surface, and means forvarying the size of said opening, the varying means being a selectivelypositionable, pivotally mounted flap, and the directing means includingan opening partially defined by a wall portion having a cross sectionsubstantially in the form of an isosceles triangle having its apexadjacent an outer end of said flap.
 4. An aircraft comprising, incombination: a. an airfoil having a surface; b. means provided on saidsurface for directing a fluid flow over substantially the entire areathereof and decreasing the pressure thereover for creating lift forcessufficient to lift the aircraft; and c. means for supplying fluid to thedirecting means, the directing means including an opening, and saidsurface having a member arranged thereon spaced from the opening andformed in the shape of an upper airfoil surface for recEiving fluid flowfrom said opening.